Why Is AUX Heat On in Mild Bandon Weather?

If your auxiliary heat is on in mild weather, it is because the controller is calling for supplemental heat. This may occur due to defrost mode, the system’s operating conditions, or temperature recovery. On its own, AUX heat does not mean that your unit is not working.

Based on NOAA’s winter outlook, Bandon and the rest of the Pacific Northwest are expected to have warmer-than-average temperatures from December through February. If your heating, ventilation, and air conditioning (HVAC) system repeatedly uses AUX heat, there may be a problem. You can reach out to Alpha Heating & Air for professional diagnostics and repairs.

What Does AUX Heat Mean on Your Thermostat?

Auxiliary heat is a supplemental heat source that is set up on some heat pumps. It will typically show up on your display screen as “AUX Heat” or “AUX.”

When auxiliary heat is on, it means your system is using a supplemental heat source, such as electric resistance heat strips. Like the coils in your toaster, these strips warm up to provide supplemental heat. Once your home has warmed up enough, auxiliary heat mode switches off.

Auxiliary heat is different from emergency heat. Instead of replacing the heat pump’s heat production, it is designed to supplement it during temperature recovery, extremely cold days, and similar situations. However, not every system contains electric strips. For example, some homes do not have any auxiliary heat equipment. In other homes, a dual-fuel system provides an additional heat source in extreme weather conditions.

Why Can Auxiliary Heat Run When It Is Not Very Cold?

So, why is auxiliary heat on when it is not cold? Should you feel concerned when you see that auxiliary heat is on?

In general, there are a few common reasons why your heat pump may switch to auxiliary heat. If you frequently notice that this mode is on, you can reach out for a professional evaluation.

A Recent Increase in the Set Temperature

If your temperature setback is significant, the heat pump may struggle to recover on its own. Because of this, auxiliary heat may kick on to help your system reach the higher setpoint target. With heat pumps, the most energy-efficient option is to set moderate temperature setbacks.

Temporary Defrost Operation

Your system’s defrost mode is one of the reasons why heat pump air may feel cool. When the system detects conditions that require defrosting, the heat pump temporarily reverses the direction of heat transfer. This allows it to warm the coil and clear the frost buildup. The blower fan continues to run during defrost operation, so the air coming from your vents may feel cool for a few minutes.

Heating Demand and Control Configuration

If your heat pump is using auxiliary heat at above-freezing temperatures, it doesn’t mean that there is a problem. The heat pump’s available output, heating demand, and control configuration determine when auxiliary heat is on. You can check the manufacturer specifications for your unit to determine when auxiliary heat should activate.

What Should You Check Before Changing Settings?

If you frequently notice auxiliary heat on in mild weather, there may be something wrong with your HVAC system or temperature settings. To troubleshoot this issue, use the following steps.

• Record the Display: First, you should note whether AUX heat is displayed on your thermostat. Pay attention to the current room reading, the requested temperature, and any error messages that may be present.
• Review Recent Changes: Next, you should consider any recent changes to your thermostat’s schedule or recent work done on the thermostat. Check to see if anyone in your home has manually increased the temperature. If there is a major change to the temperature setpoint, the auxiliary heat may kick on to help the heat pump reach the new setpoint.
• Watch Your Home’s Comfort Level: When a home is unable to reach and maintain a comfortable temperature, it is a cause for concern. Record whether your home is warming up to its target temperature or cooling off. While you make this observation, avoid repeatedly changing the temperature setting.
• Check Ordinary Airflow Conditions: Walk through your home and look for blocked vents. As you check for airflow and equipment issues, you should never remove service panels or inspect energized equipment.
• Describe the Pattern: When you call for repairs and diagnostic testing, it helps the diagnostic process if you can tell the technician what is going on. Provide context about when the issue is occurring and if it is a new problem.

To avoid having auxiliary heat on unnecessarily, you need the right thermostat schedules for Bandon homes. If you don’t already have a programmable or smart thermostat, getting one installed can help you save money on your energy costs while maintaining a comfortable indoor temperature.

When Should You Have the Heat Pump Checked?

While auxiliary heat is a normal part of your heat pump’s operations, your heat pump shouldn’t be relying on it constantly. If your heat pump has a persistent comfort shortfall or error messages appear, you should reach out for a professional evaluation. Similarly, a marked change following control work or the loss of heat are signs your system should be looked at.

During the visit, our team will establish whether your controls are calling for heat. We will determine if your equipment is delivering the correct level of heat. Our HVAC technicians will also perform tests to see if your system’s airflow, sensing configuration, and performance are functioning properly.

According to one estimate from Google Nest, running auxiliary heat strips can cost 2 to 5 times more than your heat pump’s normal operation. If you think the auxiliary heat is running longer than it should, getting the problem fixed can save you money in the long run. By reaching out to Alpha Heating & Air, you can schedule a heat pump tune-up and diagnostic services.

Questions About AUX Heat in Mild Weather

To get a better idea about what to expect and when you should call for help, check out some of our frequently asked questions.

Can AUX heat turn on when it is above freezing?

Yes, it can. Freezing is not a universal threshold for AUX heat switching on. Additionally, the outdoor coil can be colder than the air temperature, so frost and ice can build up before outdoor temperatures are below freezing.

Should I switch to Emergency Heat to stop the AUX display?

Emergency Heat is used as a backup heat source if your heat pump cannot be used, such as during a service call. It will not restore heat-pump-only operation. If your heat pump has failed or frequently relies on AUX heat, you should check your equipment manual or call our team for help.

Will avoiding large temperature changes solve the problem?

Major temperature setbacks can cause AUX heat to turn on more, but this is only one potential cause. If AUX heat keeps coming on, other factors may be involved, and a professional can determine whether the system is operating correctly.

Get Help Understanding Your Heat Pump’s Operation

Do you keep noticing auxiliary heat in mild weather? If AUX use has changed or your home remains uncomfortable, Alpha Heating & Air can help with same-day service, upfront pricing, and a money-back guarantee. We will work quickly to inspect your unit, find the source of the problem, and walk you through your repair options.

Reach out to Alpha Heating & Air at 541-238-2973 for help with your heat-pump operation and heating performance.